Molecular phylogeny and character evolution of the chthamaloid barnacles (Cirripedia: Thoracica)

作者：Perez Losada Marcos^*; Hoeg Jens T; Crandall Keith A; Achituv Yair

来源：Molecular Phylogenetics and Evolution, 2012, 65(1): 329-334.

DOI：10.1016/j.ympev.2012.06.004

• Barnacle
• Chthamaloidea
• DNA sequences
• Shell plates
• Systematics
• Taxonomy

The Chthamaloidea (Balanomorpha) present the most plesiomorphic characters in shell plates and cirri, mouthparts, and oral cone within the acorn barnacles (Thoracica: Sessilia). Due to their importance in understanding both the origin and diversification of the Balanomorpha, the evolution of the Chthamaloidea has been debated since Darwin%26apos;s seminal monographs. Theories of morphological and ontogenetic evolution suggest that the group could have evolved multiple times from pedunculated relatives and that shell plate number diminished gradually (8 -%26gt; 6 -%26gt; 4) from an ancestral state with eight wall plates surrounded by whorls of small imbricating plates; but this hypothesis has never been subjected to a rigorous phylogenetic test. Here we used multilocus sequence data and extensive taxon sampling to build a comprehensive phylogeny of the Chthamaloidea as a basis for understanding their morphological evolution. Our maximum likelihood and Bayesian analyses separate the Catophragmidae (eight shell plates and imbricating plates) from the Chthamalidae (8-4 shell plates and no imbricating plates), but do no support a gradual reduction in shell plates (8 -%26gt; 6 -%26gt; 4). This suggests that evolution at the base of the Balanomorpha involved a considerable amount of homoplasy.

• 出版日期2012-10